The present invention is directed to a bow thruster, for thrusting the bow of a boat in one direction or another, e.g., laterally to starboard or to port, to provide for a controlled, smooth docking maneuver of the boat. More particularly, the present invention is directed to a bow thruster which may be adjustably situated with respect to a stem of the boat.
Docking of water craft has generally been the most tricky maneuvering of a boat. There is not much room in adockage for maneuvering the water craft. Accordingly, a boat has to be brought into the docking area at extremely slow speed, often at or below the minimal speed required for steerage and control. Conventional power craft, or sailing vessels with an engine, are generally provided with a propeller system that rotates clockwise, when viewed in a direction facing the bow of a boat. Accordingly, this clockwise rotation of the propeller blades will tend to kick the bow of the boat laterally to port, when in forward gear. When the boat is in reverse gear, the counter clockwise rotation of the propeller blade will tend to kick the bow of the boat laterally to starboard.
Thus when approaching a dock in forward or reverse gear, the bow of the boat will tend to swing in a lateral direction, to port or to starboard. This lateral swing will become extremely pronounced, when the boat is moving at the extremely slow speeds required for safe, smooth docking. Therefore, such lateral swinging of the bow of the boat will interfere with the accomplishment of such smooth, safe docking, making it more difficult to dock the water craft, and increasing the hazards of such docking maneuvers.
Accordingly, devices known as bow thrusters have come into use for minimizing this undesired lateral swinging of the bow of the boat. Basically, these bow thrusters operate on the principle of creating force to counteract the unwanted lateral swinging of the bow of the boat, to thereby stabilize the lateral position of the bow. Such conventional bow thrusters involve disposition of a motorized propeller beneath the water line adjacent the bow of a boat, whereby rotation of the propeller blade in one direction or another can be actuated to counteract the unwanted lateral movement of the bow, i.e., by "thrusting" the bow of the boat in the opposite direction.
U.S. Pat. No. 4,223,625 discloses an outboard thruster for maneuvering a marine vessel, which is normally stowed on board the vessel. The motor-propeller unit forming this thruster is lowered into a submerged position by a retractable davit mounted on board the vessel. The motor propeller unit is connected through various cables and lines to the raising/lowering mechanism mounted on the deck of the boat.
U.S. Pat. No. 4,294,186 discloses a retractable bow thruster mounted directly within the hull of a boat. Other examples of bow thrusters may be found in U.S. Pat. No. 3,251,330 which discloses a bow thruster being lowered by a hoisting mechanism disposed on the bow of the boat through a series of interconnected links, and U.S. Pat. No. 4,208,978, which discloses a bow thruster adapted to slide along guide rods rigidly mounted upon the hull of a boat.
However, these types of conventional bow thrusters all involve considerably complicated, cumbersome arrangements, and are not feasible to activate or de-activate, especially in the extremely close quarters located in andaround dockages. Such complicated arrangements make it extremely difficult for an inexperienced crew member to activate the bow thrusters, making it necessary for a more experienced crew member to operate the same. This increases the hazards encountered on docking a vessel, because the attention of a more experienced crew member is taken away from the delicate maneuvering required in the docking of a boat. Also, the complicated nature of such thruster arrangements increase the likelihood of failure occurring in the operation thereof, especially in the raising or lowering of the respective thrusters, because a great deal of interacting components is involved.
Such types of thruster arrangements require a great deal of space for the storage thereof, especially on board or on the deck of a boat. This consumes valuable needed space upon or in a water vessel, which is always at a premium. Additionally, special mountings or fixtures for such bow thrusters are required, especially for the type mounted within the hull of a boat.